Yoroi is a light wallet for Cardano. There is no need to download the blockchain when you open the wallet.
In case you do not have ADA you can purchase these on crypto exchanges such as Coinbase, Binance, Kraken, just to name a few.
You can then keep your ADA in your own personal Cardano wallet, of which there are various.
You can send ADA to purchase the NFTs (or CNFTs) which you would then like to be able to visualize in your wallet. We recommend the following wallets: